Add rountrip test for simple email

GH rjbs#52

Show a regression introduced by commit ed7c290
which is using Email::Adress::XS to format the email
which result in stripping the 'angle brackets' around
an email when not using a 'phrase' for the email.

Previous behavior was preserving the '<quoted@email>'.

t/simple-roundtrip.t

@@ -0,0 +1,37 @@
+use strict;
+use warnings;
+use Test::More;
+use Encode;
+
+BEGIN {
+    plan skip_all => 'Email::Address::XS is required for this test'
+      unless eval { require Email::Address::XS };
+    plan 'no_plan';
+}
+
+BEGIN {
+    use_ok('Email::MIME::Encode');
+}
+
+ok !$INC{'Email/MIME/Header.pm'}, 'Email::MIME::Header not loaded';
+
+my @emails = ( q[<[email protected]>], q[[email protected]],
+    q["My Name" <[email protected]>] );
+
+foreach my $iter ( 1 .. 2 ) {
+    my $txt =
+      $iter == 1
+      ? 'Email::MIME::Header is not loaded'
+      : 'Email::MIME::Header is loaded';
+
+    foreach my $email (@emails) {
+        my $roundtrip = Email::MIME::Encode::maybe_mime_encode_header(
+            To => $email,
+            "utf-8"
+        );
+        is $roundtrip, $email, "preserve original email when $txt";
+    }
+
+    use_ok('Email::MIME::Header') if $iter == 1;
+
+}